Telephone-exchange system and apparatus.



D. B. WIGK, Jn- TELEPHONE EXGHANGE SYSTEM AND APPARATUS. APPLICATION FILED SEPT. 8, 1904.

. 904, 105. Patented Nov. 17, 1908.

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D. B. WIcK, JE- TBLEPKONE EXCHANGE SYSTEM AND APPARATUS. APPLICATION FILED SEPT. 8, 1904.

904,105. Patented Nov. 17, 1908.

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UNITED STATES PATENT OFFICE DUDLEY B. WICK, JR, OF CLEVELAND, OHIO, ASSIGN OR TO THE NORTH ELECTRIC COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

TELEPHONE-EXCHANGE SYSTEM AND APPARATUS.

Specification of Letters Patent.

Patented Nov. 17, 1908.

Application filed September 8, 1904. Serial No. 223,714.

To all whom it may concern:

Be it known that I, DUDLEY B. Wren, J r., a citizen of the United States of America, and a resident of Cleveland, in the county of Ouyahoga and State of Ohio, have in vented certain new and useful Improvements in Telephone-Exchange Systems and Apparatus, of which the following is a specification.

My invention relates to improvements in telephone exchange systems and apparatus, and has for its object, the simplification of the apparatus employed and the reduction in expense of operation and improvement of the service.

My invention relates primarily to tele phone exchanges employing common or centralized batteries, both for operating the apparatus at the exchange, and supplying current to the transmitting telephones at the sub-stations.

The system herein disclosed embodying my invention, is equipped with compound wound cut-off relays, adapted under predetermined conditions to close and open the circuit of the line signal lamp, and to introduce impedance into the circuit. In the cord circuit are provided three separate relays, two of which serve the well known function of supervisory relays, while the third or control relay is one provided with compound or diflerential windings designed to cooperate with the supervisory relays and with the associated line relays, to insure the proper operation of the system.

In the accompanying drawing, Figure 1 will be recognized as a diagram showing two subscribers stations, together with the telephone exchange, whereat their lines respectively terminate, and the cord circuit apparatus for effecting the complete connection and disconnection of said lines. Fig. 2 is an enlarged View illustrating diagrammatically the special form of relay, together with its compound and differential windings, and the positioning and connection thereof, and Fig. 3 is a somewhat enlarged and simplified diagram of the essential features of the cord-circuit, from which my invention will be more readily interpreted.

In the said drawing, I have employed the same character of reference to indicate similar parts wherever shown therein.

At the two subscribers stations A and B, is shown the usual substation apparatus employed in common battery systems. It will be assumed that subscriber A is the calling subscriber, who wishes to converse with subscriber B. Each of the lines terminate at the exchange in the answering-jacks j and the multiple jacks j; the line lamp 1 being associated with the former. Connected with the limb b of the subscribers line is the cutoff relay 0, having compound windings 0 0, while with limb a, the line relay 7' is connected, controlling the local circuit to the line signal lamp, wherein is positioned the pilot relay 7).

The control-relay c is provided with three separate windings, c e and c winding (2 being in opposition to the others. These windings are preferably positioned as indicated in Fig. 2 of the drawing; said winding a being positioned nearest the controlled armature, and winding 6 being mounted between the other windings. Springs 6 e e c and 6 are provided in the relay and diagrammatically indicated in their electrical relation in said figure. The circuits terminating respectively in these springs are controlled through the actuation of springs c c, by means of a roller-part e, mounted upon the armature c, and adapted in practice to engage the extended ends of springs e" and 6 thereby actuating them into engagement with the remaining springs of the relay, as indicated.

For the purposes of illustration, I may assume that the system is equipped with a thirty volt operating battery B, and the windings 0 will contain substantially three times the ohmic resistance of the opposing windings 6 while that of windings 0 will be substantially that of windings c. In the instance assumed, the windings 0 will be positioned between the other windings of relay 6, and occupy a central position upon the core thereof.

The line relay 1' is provided with suflicient turns to aiford an ohmic resistance of at least three times that of the combined windings of e and c of the control relay, to afford a proper working margin for the cut oil relay 0. It will be observed that the windings c necessarily bear a series relation to those of relay 1', thus materially reducing the current flow therethrough, when the call is initiated, and in practice, this reduction is made sufficient to prevent the relay 0 from operating, until the operator has inserted the corresponding plug into the spring-jack of the subscribers line. The windings 0 of the cut-0E relay normally are short circuited at contacts 0 and until said relay is sutficiently excited as above indicated, this winding, which is made of high ohmic resistance, is functionless.

Resistance w is connected in circuit between the grounded pole of battery B, the windings of supervisory relay s and the tip of the calling-plug. The usual operators telephone-set If, and calling-key 7c, are of course provided in the cord circuit, but require no description herein.

From the foregoing, the operation of the system will, I think, be readily understood. hen subscriber A lifts his receiver from the telephone hook, the limbs a b are closed together at the subscribers switch-hook, thereby causing the current to flow from the live pole of battery B, through the wind-v ings of relay 1", contacts 0 conductor a, through the sub-station and back via conductor Z), contact 0 windings 0, conductors 2 3, to the grounded pole of the battery. This, of course, closes the local circuit of the line signal lamp 1, which, being observed by the operator, is answered by the insertion of the plug p into the subscribers ack j.

Because of the relatively small number of turns in windings 0", and the resistance in circuit therewith, the cut-off relay 0 must remain inert during the initial flow of current, which condition obtains until the answeringlug has been inserted in the spring-jack. When this occurs however, a new low resistance path for the exciting current is established through the opposing windings of the control-relay, which may be traced from the live pole of the battery B, conductors at 5, windings e in a clock-wise direction, conductors 6 7, windings e in a contra-clockwise direction, conductor 8 to the sleeve of the answering-plug, the test ring of the jack j, extended limb b of the subscribers line, contacts 0 windings 0, and conductors 2 3, to the opposite pole of the battery.

The current flow through the active windings of cut-0E relay 0 is thereby materially augmented, since the resistance of the subscribers line and of relay 1" has been eliminated, and both armatures of said cut-off relay are immediately actuated to open their contacts 0 0 By this action, two functions are immediately subserved; the first being the extinction of the line signal lamp, and the other, the introduction of the high impedance windings 0 of the relay directly into circuit with conductor 6, which serves to effectually reduce the consumption of current, and to prevent the undesired passage of telephonic voice currents therethrough.

hen the operator has ascertained the number of the subscriber desired, she will make the usual busy-test, by touching the tip of the calling-plug 7) to the test ring of the subscribers line, (circuit being established from the grounded side of the battery B and through the relatively high resistance 'w) and ascertaining that said line is not in use, she will insert the plug 7) into the available multiple jack, and ring the subscriber after the usual manner. Up to this point, the control-relay has not operated, since the more favorably positioned windings e effectively oppose the rearwardly mounted windings 6 upon the core of the relay, and practically neutralize each other. But the flow of current being established through the additional windings 0, upon the insertion of the calling-plug, said relay will be actuated to establish circuit between its several contacts, by current flowing from the live pole battery B, conductor 9, windings e, conductor 10, through the operators key to the sleeve of plug 22', the ring of the containing ack, limb Z) of the subscribers extended line, relay (2, conductors 2, 3, to the opposite pole of the battery. By this actuation of the relay a shunt about the resistance to is established at contact 0, thus allowing the normal battery feed to be supplied to the tip side of the called line; while circuit is closed between springs a e and 6 to short-circuit the opposing windings e 7 thus insuring equalized battery feed to the subscribers instruments, by placing in circuit the two equal windings e and c and to supply current to one side of the local circuit 12 for the supervisory lamps, which of 'course remain unlighted, since their respective armatures have been excited to open the local circuits at their contacts. This condition of course obtains, during the continuance of conversation; the supervisory lamps lighting after the usual manner, only when the subscribers respectively hang their receivers upon their switch-hooks.

From the foregoing description of the apparatus and its operation, those skilled in the art will appreciate the extreme simplicity of the system set forth, and the economies and advantages attained in employing the same. I may summarize merely by pointing out that the action of the cut-off relays, although initially excited, is deferred until the proper time for extinguishing the line signal, or opening the circuit thereto; whereupon the high impedance windings thereof are brought into play, and the lamp relay is disconnected from the line.

lVith respect to the control-relay, it is seen that although initially used to supply current to the answering side 'of the cord circuit, I have caused it to remain inert, by suitably proportioning and positioning the opposing windings thereof, through which the battery feed is established; while upon inserting the calling-plug, the opposing windings are overcome or shunted out, and

current flow is established, preferably through co-acting windings of the relay, to maintain the regular circuit connections during the insertion of the connecting plugs.

Having now described a system and apparatus embodying my improvements, I claim as new, and desire to secure by Letters Patent, the following 1. In a telephone exchange system, the combination with the cord circuit of a control-relay associated therein, having opposingwindings, supervisory signals governed partially by said relay, a circuit serially containing the opposing windings, adapted to be closed upon the insertion of one plug in its spring-jack, whereby current is fed through the relay withoutcausing its excitation, and a second circuit containing a relay winding, closed upon the insertion of the other plug in its spring-jack, whereby said relay is actuated to effect the control of its connected circuits, substantially as set forth.

2. In a telephone exchange system, the combination with a control-relay having a plurality of windings connected in the cord circuit, two of which are opposing windings, a cut-off relay adapted to become excited by current supplied through the opposing windings of the control-relay, and an additional winding upon the control-relay, adapted to excite the same upon the completion of connection through the cord circuit, substantially as set forth.

3. In a telephone exchange system, the combination with a subscribers line terminating at the exchange, a signaling relay, and a cut-off relay associated serially with the line, the latter having two windings respectively of low resistance and of a normally shunted high impedance, a cont-rolrelay associated in the cord circuit, and having opposing windings through which battery feed is established upon the insertion of a plug in the spring-jack, substantially as set forth.

t. In a telephone exchange system, the combination with a snbscribers line terminating at the exehange,-a signaling relay, and a cut-off relay associated serially with the line, the latter having two windings respectively of low resistance and of a normally shunted high impedance, a controlrelay associated in the cord circuit, and having opposing windings approximately onethird the resistance of the line signaling relay, through which battery feed is established upon the insertion of a plug in the spring-jack, substantially as set forth.

5. In a telephone exchange system, the combination with the subscribers lines terminating at the exchange, of line signals associated therewith, a line relay, and a cutoff relay connected with each of the sub scribers lines, the latter having a low resistance winding and a normally shunted winding of high impedance, a control-relay e in the cord circuit, supervisory signals, and a resistance associated with the tip strand of the calling-plug, respectively governed by said control-relay, substantially as set forth.

6. In a telephone exchange system, the combination in the cord circuit thereof, with a control-relay, of a resistance normally connected in the test circuit, and means under the control of said relay, for short circuiting said resistance, and supplying normal bat tery feed to the line upon the insertion of the calling-plug, substantially as set forth.

Signed at Cleveland, this 3rd day of Sept. 1904, in the presence of two subscribing witnesses.

DUDLEY 13. WIOK, JR.

Vitnesses:

RUTH SUTPHEN 10K, ALBERT LYNN LAWRENCE. 

